Type 2 diabetes (T2D) is an independent risk factor for cognitive impairment. The dysregulation of hypoxia inducible factor (HIF) signaling in T2D patients results in impaired adaptive responses to hypoxia, thereby accelerating the progression of complications. However, limited knowledge is available regarding its precise function in diabetes-associated cognitive impairment (DACI). Here, elevated HIF-1α levels were observed in brain endothelial cells (ECs) of db/db mice. Functionally, brain ECs-specific knockdown of H if1 a significantly ameliorated T2D-induced memory loss and neuronal damage. Glycolysis in brain ECs was inhibited in this process, as indicated by RNA-seq, leading to decreased hippocampal lactate production through reduced LDHA expression. Notably, T2D patients showed increased cerebrospinal fluid lactate levels, which were strongly associated with their cognitive dysfunction. Intrahippocampal injection of lactate accelerated cognitive dysfunction and impaired adult hippocampal neurogenesis (AHN) in db/db mice. Conversely, reducing hippocampal lactate levels through the intrahippocampal injection of oxamate delayed the onset of memory deficits. Furthermore, asiatic acid was discovered to protect db/db mice from cognitive impairment by decreasing brain endothelial HIF-1α expression and subsequently reducing hippocampal lactate-induced AHN damage. Overall, this study elucidates the inhibiting role played by endothelial HIF-1α-driven lactate in AHN and highlights a potential tactic of targeting HIF-1α in brain ECs for treating cognitive impairment.

OBJECTIVE To study the neuroprotective effects of Shenzao jianna o oral liquid （SZJN）on Alzheimer ’s disease （AD）model mice and its mechanism. METHODS The mice were randomly divided into sham operation group ，model group ， Donepezil hydrochloride tablet group （0.65 mg/kg），SZJN low-dose ，medium-dose and high-dose groups （0.3，1.5 and 7.5 g/kg， calculated by crude drug quantity ），with 12 mice in each group ，half male and half female. Each group was given relevant medicine（intragastric administration of water at constant volume in sham operation group and model group ），twice a day ，for consecutive 28 d. On the 15th day of administration ，intracerebroventricular injection of β-amyloid 1-42（Aβ1-42）combined with intraperitoneal injection of scopolamine hydrobromide were used to induce AD model. Morris water maze was used to detect the learning and memory ability of mice. HE staining and Nissl staining were used to evaluate the pathological changes of brain tissue in mice. The levels of MDA and SOD in brain tissue of mice were detected. The phosphorylation level of cyclic adenosine monophosphate response element binding protein （CREB） and expression of brain-derived neurotrophic factor （BDNF） in hippocampal tissues were detected by Western blot. RESULTS Compared with sham operation group ，the escape latency of the model group was significantly prolonged ，and the number of crossing the platform and the percentage of residence time in the target quadrant were significantly reduced （P＜0.01）. The level of SOD in brain tissue ，the phosphorylation level of CREB and the expression level of BDNF in hippocampus decreased significantly （P＜0.01），while the level of MDA increased significantly （P＜ 0.01）. In hippocampal CA 1 area and cortical tissue ，nerve cells showed significantly decreased number ，the disordered arrangement and large gap ；the shape of nucleus was irregular and deeply stained ，and Nissl body was blurred ，loosely arranged and the number decreased. Compared with model group ，the escape latency of mice in each dose group of SZJN was significantly shortened ，and the times of crossing the platform and the percentage of residence time in the target quadrant were significantly jing- increased（P＜0.01）. Above indexes of brain tissue in mice were reversed sig nificantly in SZJN high-dose group （P＜0.01），and pathological damage of brain tiss ue was improved. CONCLUSIONS SZJN can significantly improve the learning and memory ability of AD model mice ，and alleviate the pathological injury and oxidative stress of brain tissue ，which may be related to the activation of CREB/BDNF signaling pathway.

Objective To study the effects of PHLDA2 overexpression on radiosensitivity and the underlying mechanisms in human osteosarcoma U2OS cell line.Methods To obtain the subclone,cells were exposed to G418 persistently after transfection of pEGFP-C3-PHLDA2 vector into U2OS cells.Three groups of blank control (U2OS),negative control (U2OS-neo) and transfected group (U2OS-PHLDA2) were used.The expression of PHLDA2 in the subclone cells was determined by Western blot.After exposure to X-ray irradiation,cellular growth activity and survival were detected by CKK-8 assay and colony formation assay,respectively.The cell apoptosis was measured by the Annexin V/PI staining,and the apoptotic protein was analyzed by Western blot.The in-vivo effects of PHLDA2 on irradiation were evaluated by xenografts.Results Compared with U2OS group and U2OS-neogroup,the sabclone cells were successfully obtained by G418 selection,in which the expression of PHLDA2 was upregulated(t =13.73,16.28,P ＜ 0.05).In vitro,PHLDA2 overexpression significantly enhanced the response to radiation in U2OS cells with a reduction of colony survival and proliferation with the increase of doses (t =5.00-8.23,P ＜0.05;t =-2.52--1.26,P ＜ 0.05).In vivo,PHLDA2-upregulated xenografts had more radiosensitivity than control groups with a significant inhibition of tumor growth (t =3.27,2.91,P ＜ 0.05).After 8 Gy irradiation,the apoptosis was significantly increased (t =10.11,9.61,P ＜ 0.05),accompanied with the activation of Caspased-3 in U2OS-PHLDA2 cells,which was presented by upregulation of cleaved Caspase-3 (t =11.26,10.72,P ＜ 0.05).Conclusions Exogenetic expression of PHLDA2 could significantly enhance the radiosensitivity of human osteosarcoma cells,which may be attributed to the activation of Caspase-3 that increases irradiation-induced apoptosis.